1. Field of the Invention
The present invention relates generally to ophthalmic lens storage containers each having a lens storage portion for storing an ophthalmic lens such as a contact lens, more particularly to such an ophthalmic lens storage container having a novel structure to facilitate removal of the ophthalmic lens from the lens storage portion.
2. Description of the Related Art
A blister package is known as one type of a container for storing a contact lens. JP-A-7-322911, JP-A-9-23916, JP-A-10-313928 and U.S. Pat. No. 6,050,398 disclose known examples of the blister package that includes: a package body having a generally semi-spherical cavity and a flange extending radially outward around the periphery of the cavity; and a cover sheet formed of a plastic film, aluminum foil or the like. The cavity contains the contact lens and a preserving solution, and the cover sheet is stripably sealed to the flange in a sealing zone that extends around the periphery of the cavity, to thereby enclose the cavity.
The conventional blister package constructed as described above may suffer from a problem that the sealing zone formed in the flange of the package body is roughed once the cover sheet is stripped or peeled from the flange, being likely to cause undesirable generation of burrs or fuzz on the sealing zone extending around the periphery of the cavity. Generally, a user removes the lens from the cavity by sliding the Ilens up along the bottom surface and the open-end peripheral surface in this order, while pushing or gripping the lens by his or her fingers. Accordingly, the contact lens may come into contact with the burrs left on the sealing zone, and is likely to be damaged, e.g., occurrence of flaws or cracks on the surface of the lens, by the contact with the burrs. Especially, a contact lens of disposable type, which has relatively thin wall thickness and a low strength, is more likely to be damaged by the contact with the burrs, upon the removal of the lens from the lens storage container.
In a lens container of this type, it is sometimes necessary to pour off only the liquid contained in the cavity, while keeping the contact lens stored within the cavity. As a specific example, in some instances the contact lens provider, at some point up to the process where a contact lens and a preserving solution are stored in the cavity and sealed with a cover, may employ a procedure of placing the contact lens together with a treatment solution such as a cleaning solution in the cavity and subject it to appropriate treatment, after which the treatment solution only is poured off while leaving the contact lens, followed by injection of preserving solution. Also, in some instances, the user of the contact lens, after peeling off the cover to expose the cavity, may drain off only the preserving solution, and then remove the contact lens remaining in the cavity.
When a liquid contained in the cavity is to be drained off while keeping the contact lens within the cavity in this manner, there is a need to carry out the procedure easily and reliably. Therefore, it is desirable that without any special utensil, it be possible to detain the contact lens within the lens container when tilted, so that only the liquid can be drained from a particular location along the circumference at the rim of the cavity opening.
The lens containers of conventional design taught in the patent publications cited hereinabove have not been examined in this regard, as many of them employ a cavity inside shape that is a simply concave spherical shape. While improvements have been proposed, these have consisted simply in providing a slope so as to facilitate removal of the contact lens.
Accordingly, a problem to date has been that when liquid is poured off from the cavity as described above, the contact lens tends to be carried out together as well, making the procedure difficult.